Electrical systems can include devices for switching of electric power, such as a relay. A relay, such as an electromechanical relay, can include one or more contacts for switching power from a power source to a load, such as an electrical device. Detecting the position of a contact of a relay can be used to determine whether the relay is functional. Detecting the position of a contact of a relay can also provide a notification that a relay is in a closed position and that a high voltage is present on the output of the relay.
Detecting the duration of the movement of an armature of a relay from a first contact position, such as an open position preventing current from flowing between a power source and a load, to a second contact position, such as a closed position allowing current to flow between a power source and a load, can also present advantages. The operational lifespan of a relay can be increased by switching power to a load at a point at which a sinusoidal input voltage or current from a power source has a zero value (“a zero crossing”). Such loads can include a purely reactive load (including inductive and capacitive), resistive load, and any combination of the resistive and reactive loads. Setting a relay to a closed position at or near a point in time associated with the zero crossing of the input line voltage can significantly reduce or completely eliminate an inrush current to a reactive load.
The duration involved in actuating a relay from an open position to a closed position can vary significantly between relays. The actuation duration can be the difference between a first point in time at which a relay is actuated and a second point in time at which a contact of a relay is at a closed position. Configuring the timing for actuating a relay can include offsetting a point in time at which a relay is actuated from a point in time associated with a zero crossing.
Previous solutions for detecting the position of a contact in applications involving switching multiple voltages can include complex detection circuitry rated for use with relays switching high voltages, thereby increasing the overall cost of the solution and decreasing the reliability of the product for which the solution is used.
Accordingly, simplified systems and methods for determining the actuation duration are desirable.